Great Barrier Reef pronounced as ‘almost dead’ by scientists

Scientists have warned that the Great Barrier Reef – the world’s largest structure of living organisms – is “almost dead”.

New images show that the 25 million year old reef has finally succumbed to coral bleaching, a result of rising water temperatures because of climate change.

Researchers in May found that over a third of the coral in the northern and central parts of the reefs were dead, and that 93% of individual reefs had been affected by coral bleaching. The warming of the oceans causes corals to expel their algae and become bare. Without their algae, corals cannot access any nutrients.

“After the bleaching event in May, 60% of what we saw was bleached very white,” Australian Climate Change CEO Amanda McKenzie said. Another 19-20% was covered in sludgy brown algae. Even of what remained healthy, some looked a bit on edge. When we went back a few weeks ago to see if they had recovered or died, quite a large proportion had died.”

She estimated that around half the bleached corals they had visited had died and that the bleaching had mostly affected delicate corals rather than the stronger brain corals.

Professor Tim Flannery, who visited the reef in September, told ABC: “There’s a whole lot of white coral out there that’s been killed by Crown of Thorns starfish because it was too weak to defend itself.”

Tourism operator John Rummey, who has been visiting the reef for the past 15 years, said that had also noticed a decrease in the amount of fish.

“The experience is still fantastic, but tourists don’t know what they’re looking at. They don’t know what it should look like.”